Women who enter menopause at an earlier age have shortened reproductive life spans and are at an increased risk for adverse health outcomes later in life. It is unclear why some women enter menopause earlier than others; however, it has been suggested that environmental exposures may play some role. Specifically, lead which is ubiquitous in the environment has been implicated as a potential endocrine disrupter, having been associated with a number of adverse reproductive outcomes. The proposed pilot study will investigate the association between lead exposure and hormonal markers of reproductive senescence that are highly predictive of the menopausal transition. Pre- and perimenopausal women (n=40) will be recruited through a gynecology clinic in Cleveland, OH and followed for 12 months. Each woman will have three study visits, approximately six months apart. Study visits will be scheduled for days 3-5 of the menstrual cycle, with day 1 represented as the first full day of bleeding. Blood lead levels, hormones and markers of bone turnover will be measured at all 3 visits, and bone lead levels measured at baseline and 12 months. Over the 12 month study period, women will be asked to maintain a monthly diary indicating days on which they had menstrual spotting or bleeding. The proposed study will determine the feasibility and provide the potential foundation for a larger and more informative cohort study on the environment and menopause that would follow women prospectively to assess changes in hormone levels, progression through the menopausal transition, and ultimately age at menopause. Cleveland provides the ideal setting for the proposed study given the continued high levels of lead and other exposures that exist in the environment and the interaction of these exposures with social and ethnic factors leading to health disparities. Should significant health effects be found, further efforts would be made to translate the results into effective policy to limit potential exposures, decrease health disparities, and inform women and health care professionals regarding the potential health hazards and need for screening. [unreadable] [unreadable] [unreadable]